The 9th Gordon Research Conference (GRC) on Antimicrobial Peptides (AMPs) will meet in Ventura, CA, from February 24-March 1. AMPs are endogenous components of innate immunity used by all metazoans including bacteria, fungi, plants, invertebrates, vertebrates, and mammals including humans. They act as natural antibiotics by prohibiting invasion and killing pathogens, and by restricting growth of non-pathogenic microbes. The emergence of antibiotic-resistant microorganisms underscores the need to study AMPs. Furthermore, additional evidence shows that AMPs mediate host defense in a variety of biological settings and can act in ways distinct from their antimicrobial function, via receptor-mediated inflammation- associated activities such as chemotaxis or induction of cytokine production, supporting the hypothesis that AMPs are multifunctional host defense effector molecules. Recent evidence indicates a role of microbe- and host-derived AMPs in maintaining regulating the composition of the commensal microbiota and protection of the host from infection. Knowledge of the roles of AMPs in immune responses will contribute to improved understanding and treatment of the pathophysiology of human diseases, including inflammatory bowel disease, sexually transmitted and opportunistic infections, atopic dermatitis, and others. The program will be divided into 9 sessions of oral presentations and four poster sessions. The conference is co-chaired by Drs. Nita Salzman and Gill Diamond, together with the co-vice-chairs, Drs. Julia Dorin and Pieter Hiemstra, and will open with a keynote address presented by Professor Jules Hoffmann. Special attention will be made to include junior faculty and student participants. Speakers will include those selected in advance based on recent important discoveries, and those selected from submitted abstracts. Session topics will include: Conservation of Antibacterial Host Defense; AMPs as Antivirals; Host Defense against Fungi and Parasites; Cyclic AMPs; AMPs at the Interface; Antimicrobial and Beyond; AMPs and Immunity; and Novel Technologies and Applications for AMPs. Ample time for organized discussion and informal interactions between participants has been included. In addition, daily sessions, including Hot Corner and Late Breaking News will be devoted to discussing topics at the cutting edge of current investigation. The organizational philosophy is to encourage diverse participation, and maintain an eye towards gender issues, junior scientists, minorities, and individuals with physical limitations.